1. Field of the Invention
This invention relates to a cylinder block for an internal combustion engine, and more particularly to a cylinder block made of light alloy and produced by die-casting.
2. Description of the Prior Art
It is well known to die cast a cylinder block using a light alloy such as aluminum alloy as a material thereof. Such a die-cast cylinder block is not provided with an upper deck section, so that the top section of each engine cylinder is not integrally connected to an outer wall structural of the cylinder block. In this connection, the upper deck section in a cylinder block produced by conventional casting using molding sand is provided with such a upper deck section which serves to integrally connect each engine cylinder top section and the outer wall section of the cylinder block. The reason why the deck section is not provided in the die-cast cylinder block is that a metallic die for forming the water jacket is pulled up during die-casting thereof. As a result, the upper section of each engine cylinder is not integral with the outer wall section of the cylinder block and is accordingly, free from secure restraint. This leads to a reduction in flexural and which results in vibrations and, thus, of the cylinder block, thereby readily vibrating to generate noise.